This K01 application proposes career development and research activities customized to facilitate the candidate's (Dr. Noah Webster) transition from conducting basic social science research to behavioral intervention research. The candidate's long-term career goals include becoming an independent research scientist conducting research aimed at: a) improving the health and independence of older adults; and b) reducing later life health disparities. This will involve developing, testing, implementing, and disseminating a social network-based intervention to improve participation in behavioral health (e.g., physical activity) interventions within low resource settings. Career Development/Training Aims: In order to accomplish career goals the candidate is in need of targeted and interdisciplinary training in: 1) intervention development; 2) intervention evaluation; and 3) objective assessment of physical activity. This training will be facilitated through coursework and interactions with an interdisciplinary mentoring team led by Dr. Neil Alexander. Training Environment: The candidate is situated within the largest academically-based social science institute in the world. The resources available to him at the Institute for Social Research as well as the University of Michigan's Schools of Medicine and Public Health together offer an unparalleled supportive and stimulating environment for conducting research at the intersection of social science and intervention research. Research Aims: While only 16% of people age 65+ engage in recommended physical activity levels, increases may be achieved through activation of social resources. A social network-based approach that systematically identifies and involves influential agents of change in a community is proposed to facilitate physical activity-related information dissemination and behavior change. This project will leverage Go4Life, NIA's evidence-based physical activity campaign and capitalize on the strength of social ties. The intervention addresses socio- economically linked health disparities by developing the intervention for use in affordable (HUD subsidized) senior housing. The project will address three specific aims: Aim 1) Identify agents of change in an affordable senior housing community who will then be invited to form a committee to disseminate Go4Life materials through planning, publicizing, and participating in community-wide activities over 12 months. Aim 2) Evaluate intervention feasibility using a mixed methods approach. Aim 3) Establish preliminary network effect on changes in physical activity and identify influential network mechanisms. The proposed feasibility study is the first step in using locally available and low-cost resources to affect behavior change among socio-economically vulnerable senior housing residents. In the short-term, findings will provide preliminary data to conduct a multi- site efficacy trial which will implement and evaluate successful components of the intervention. In the long- term, understanding how to leverage social networks to promote and sustain increases in physical activity will provide key information to advance the science of behavior change as well as reduce health disparities.